RE: fs racing 4wd?
For an FS, which it supposed to include everything, yes, over $600 is actually too much. FS RCs, complete with engine, radio, RX, and servos in RTR, do not cost anything more than about $550 USD.
I suggest you get a hold of Ken (the guy from engagerc) and get your money back ASAP. If you still want an FS, really look at buying from a different seller; I know you can get a much better price for an FS.